WO2021098857A1 - 量子点及其制备方法、量子点组合物、光电器件 - Google Patents

量子点及其制备方法、量子点组合物、光电器件 Download PDF

Info

Publication number
WO2021098857A1
WO2021098857A1 PCT/CN2020/130633 CN2020130633W WO2021098857A1 WO 2021098857 A1 WO2021098857 A1 WO 2021098857A1 CN 2020130633 W CN2020130633 W CN 2020130633W WO 2021098857 A1 WO2021098857 A1 WO 2021098857A1
Authority
WO
WIPO (PCT)
Prior art keywords
quantum dots
precursor
solution
quantum dot
alloy
Prior art date
Application number
PCT/CN2020/130633
Other languages
English (en)
French (fr)
Inventor
胡保忠
高远
毛雁宏
李光旭
Original Assignee
纳晶科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 纳晶科技股份有限公司 filed Critical 纳晶科技股份有限公司
Priority to US17/777,657 priority Critical patent/US20220403240A1/en
Publication of WO2021098857A1 publication Critical patent/WO2021098857A1/zh

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C09K11/562—Chalcogenides
    • C09K11/565—Chalcogenides with zinc cadmium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/54—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing zinc or cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • C09K11/881—Chalcogenides
    • C09K11/883—Chalcogenides with zinc or cadmium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0008—Processes
    • H01L2933/0033—Processes relating to semiconductor body packages
    • H01L2933/0041—Processes relating to semiconductor body packages relating to wavelength conversion elements

Definitions

  • This application relates to the technical field of quantum dots, in particular to quantum dots and preparation methods thereof, quantum dot compositions, and optoelectronic devices.
  • the device external quantum efficiency (EQE) of blue quantum dots such as CdZnS/ZnS, CdZnSeS/ZnS, ZnCdSe/ZnS has reached more than 10%, and the maximum brightness has exceeded 10,000 cd/m 2 .
  • the outer layer of this kind of blue quantum dots is covered with a thicker ZnS shell, which results in a deeper HOMO energy level (that is, a larger absolute value) and the lowest unoccupied molecular orbital of the blue quantum dots.
  • the (LUMO) energy level is relatively high, which is not conducive to the effective injection of carriers, so that the life of such blue quantum dot optoelectronic devices generally does not exceed 1000 hours, which is far from meeting the minimum requirements for commercialization.
  • the prior art proposes to coat ZnCdSe with a ZnSe shell layer of about 7nm thickness, which can effectively increase the HOMO energy level of blue quantum dots and shorten the energy level gap between it and the hole transport layer TFB material, making this type of blue light
  • the photoelectric device of the quantum dot reaches the level of 7000h under the lighting condition of 100cd/m 2 , which is significantly longer than the lifetime of the quantum dot coated with a ZnS shell.
  • this type of blue quantum dot optoelectronic device can only achieve the highest value of the external quantum dot efficiency (EQE) under the lighting condition of 10,000 cd/m 2 , and the operating current density of the optoelectronic device at this time is 88 mA/cm 2 . Therefore, under the actual commercialized brightness of 50cd/m 2 ⁇ 200cd/m 2 of the optoelectronic device of this kind of blue quantum dots, the EQE attenuates to 3%, and the external quantum efficiency is extremely low, which is far from meeting commercial requirements.
  • EQE external quantum dot efficiency
  • EQE After being applied to optoelectronic devices , EQE reaches its maximum value at a working current density of 5mA/cm 2 ⁇ 20mA/cm 2 , and the life of optoelectronic devices is longer, which more satisfies actual commercial requirements.
  • a quantum dot comprising a core and a shell layer covering the core, the material of the core is CdZnSe, the material of the shell is CdZnS, wherein the combination of the Cd element and the S element in the shell
  • the molar ratio is 0.15:1 to 0.4:1.
  • the average particle size of the inner core is 3 nm to 10 nm
  • the thickness of the shell layer is 3 nm to 10 nm.
  • the average particle size of the inner core is 5 nm to 9 nm, and the thickness of the shell layer is 3 nm to 5 nm.
  • the fluorescence emission wavelength of the aforementioned quantum dots is 460 nm to 480 nm.
  • the fluorescence emission wavelength of the aforementioned quantum dots is 470 nm to 480 nm.
  • a method for preparing quantum dots as described above including the steps of: preparing an inner core; mixing the inner core with a first zinc precursor, aliphatic amine, and a solvent to form a first precursor solution, and then A cadmium precursor and a first sulfur precursor are added to the first precursor solution separately or together at a uniform rate to form a second precursor solution.
  • the molar ratio of Cd element to S element in the second precursor solution is 0.15:1 ⁇ 0.4:1; the second precursor solution is reacted at a first temperature to coat the surface of the inner core to form a shell layer to obtain quantum dots.
  • the preparation process of the above-mentioned inner core includes: mixing a second zinc precursor, a first selenium precursor, a second cadmium precursor, and a solvent, and reacting at a second temperature to obtain a solution containing the first alloy quantum dots, The first alloy quantum dots are purified as the core.
  • the method further includes adding a second selenium precursor and reacting at the third temperature to obtain the above-mentioned solution containing the first alloy quantum dots.
  • the preparation process of the above-mentioned inner core further includes:
  • steps (2) and (3) are repeated at least n times for continued growth.
  • the n+1th alloy quantum dot solution replaces the first intermediate solution in step (1) to obtain
  • the n+2th alloy quantum dot is purified as the inner core, and n is a positive integer greater than or equal to 1.
  • the molar ratio of the long-chain fatty acid to the zinc short-chain fatty acid is greater than or equal to 2:1.
  • the molar ratio of the long-chain fatty acid to the zinc short-chain fatty acid is 2:1 to 4:1.
  • the molar ratio of the selenium element in the third selenium precursor to the zinc element in the second intermediate solution is 1:2 to 2:1, and the molar concentration of the selenium element in the third selenium precursor is 0.5 mmol /mL ⁇ 4mmol/mL.
  • the thickness of the growth is less than or equal to 1.5 nm; and, when the n+1th alloy quantum dots continue to grow into the n+2th alloy quantum dots, every time The thickness of the growth is less than or equal to 1.5nm.
  • the solution of the i+1th alloy quantum dots replaces the above-mentioned first intermediate solution in step (1) to obtain a solution containing the i+2th alloy quantum dots, and the i+2th alloy quantum dots
  • the alloy quantum dots are purified as the above-mentioned core, and the above-mentioned i is a positive integer smaller than the above-mentioned n.
  • the inner core Prepare the inner core; mix the inner core with the first zinc precursor, fatty alcohol, and solvent to form a first precursor solution, and then add the first cadmium precursor and the first sulfur precursor to the first precursor solution separately or together at a uniform rate
  • the molar ratio of the Cd element to the S element in the second precursor solution is 0.15:1 to 0.4:1; the second precursor solution is reacted at the first temperature so as to The surface of the core is coated to form a shell layer to obtain quantum dots.
  • fatty alcohol is selected from fatty alcohols having a carbon chain length of 12-30.
  • a quantum dot composition which includes the above quantum dot or the quantum dot prepared by the above preparation method.
  • a photoelectric device which includes the quantum dots described above or the quantum dots prepared by the preparation method described above.
  • the optoelectronic device is a quantum dot light-emitting diode, and when the quantum dot light-emitting diode reaches the highest external quantum efficiency, the required operating current density is 5mA/cm 2 ⁇ 20mA/cm 2 , and the above-mentioned highest external quantum efficiency is 9.6% ⁇ 12.6 %.
  • the quantum dots of the present application use CdZnSe material with shallow HOMO energy level as the core, which is more conducive to the injection of holes.
  • the homogeneous CdZnS material with low LUMO energy level is used as the shell layer, and the Cd element and S element in the shell layer
  • the molar ratio is 0.15:1 to 0.4:1, which has a better energy level structure and is more conducive to the injection of electrons, so that the carrier injection barrier of the quantum dots of the present application is lower, which is more conducive to carriers Injection.
  • the EQE reaches the maximum value at a low operating current density of 5 mA/cm 2 to 20 mA/cm 2, and the maximum EQE value can reach 9.6% to 12.6%.
  • the life of the optoelectronic device is longer, and it is easier to meet the actual commercialization requirements of blue QLEDs.
  • Fig. 1 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 1;
  • Fig. 2 is a current density-EQE curve diagram of the quantum dot light emitting diode of Example 2;
  • Fig. 3 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 3;
  • Example 4 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 4;
  • Fig. 5 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 5;
  • Example 6 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 6;
  • Fig. 7 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 7;
  • Fig. 8 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Example 8.
  • Fig. 9 is a current density-EQE curve diagram of the quantum dot light-emitting diode of Comparative Example 1;
  • Fig. 10 is a current density-EQE curve diagram of a quantum dot light-emitting diode of Comparative Example 2;
  • Fig. 11 is a current density-EQE curve diagram of a quantum dot light emitting diode of Comparative Example 3;
  • FIG. 12 is a current density-EQE curve diagram of a quantum dot light-emitting diode of Comparative Example 4.
  • FIG. 12 is a current density-EQE curve diagram of a quantum dot light-emitting diode of Comparative Example 4.
  • quantum dot and its preparation method, quantum dot composition, and optoelectronic device provided in the present application will be further described below.
  • the quantum dots provided in this application have a fluorescence emission wavelength of 460 nm to 480 nm, preferably 470 nm to 480 nm, and are blue quantum dots.
  • the photoelectric device using the quantum dots has a maximum working current density of 5mA/cm 2 to 20mA/cm 2 , and the EQE reaches the maximum value.
  • the lifetime of T50 is greater than or equal to 10000h under the lighting condition of 100cd/m 2, which is a kind of low working current.
  • the quantum dot includes a core and a shell covering the core.
  • the material of the core is CdZnSe
  • the material of the shell is CdZnS.
  • the molar ratio of Cd element to S element is 0.15:1 to 0.4:1.
  • the molar ratio of Cd element to S element in the shell layer can be determined by the molar ratio of Cd element to S element contained in the added raw material (ie, the second precursor solution described below) to obtain the Cd element and S element in the shell layer.
  • the molar ratio of the elements is about 0.15:1 to 0.4:1.
  • the molar ratio of Cd element to S element in the shell layer can be obtained by ICP detection and analysis.
  • the CdZnS material has a lower LUMO energy level compared to ZnS. Therefore, when the CdZnS material is used as the shell layer, it is more conducive to electron injection. More importantly, the applicant of this application has discovered through long-term and in-depth research that when the CdZnS material is used as the shell layer, the content of Cd element directly affects the energy band structure of the CdZnS shell layer, while the energy band structure of the CdZnS shell layer directly affects The performance of optoelectronic devices using the quantum dots.
  • the energy band structure of the CdZnS shell is better, and the LUMO energy level is lower, which is more conducive to electron injection , And as the molar ratio of Cd element increases, the effect becomes more significant.
  • the CdZnSe material has a shallower HOMO energy level compared to the CdZnS material and the CdZnSeS material. Therefore, using the CdZnSe material as the core is more conducive to hole injection.
  • the CdZnSe material is used as the core, which has a better matching relationship with the CdZnS shell layer with the above-mentioned element molar ratio. Therefore, quantum dots with CdZnSe material as the core and CdZnS material with the above-mentioned element molar ratio as the shell have a lower carrier injection barrier, which is more conducive to carrier injection. After being applied to optoelectronic devices, the electroluminescence efficiency of optoelectronic devices is higher, the working current density is lower, and the life is longer, and it is easier to meet actual commercial requirements.
  • the above-mentioned shell layer is a homogeneous CdZnS shell layer, that is, the distribution of Cd in the shell layer is uniform, so that the energy band structure of the shell layer is better.
  • the shell layer is homogeneous or not, due to the limitation of the existing technical level, it can be judged whether the shell layer is homogeneous or not by referring to the feeding method of the quantum dot preparation method.
  • the average particle size of the core is 3 nm-10 nm
  • the thickness of the shell layer is 3 nm-10 nm.
  • the average particle size of the inner core is 5 nm to 9 nm, and the thickness of the shell layer is 3 nm to 5 nm.
  • the effect of covering different thickness of the shell layer is not much different, but the emission wavelength may be different.
  • the quantum dots prepared in the same batch may have a relatively constant particle shape, and the average particle size is determined by transmission electron microscope images, but is not limited thereto.
  • the average particle diameter of the aforementioned quantum dot may be a diameter.
  • the average particle diameter of the quantum dots may be the diameter of a circle with an equivalent (equal) area calculated from the two-dimensional area of the electron microscope image of the quantum dot.
  • the thickness of the shell layer can be obtained by measuring the average particle size of the quantum dots after coating the shell layer, and then subtracting the average particle size of the corresponding core.
  • the fluorescence emission wavelength of the quantum dots is 460 nm to 480 nm, so as to ensure that the quantum dots are blue quantum dots. In some embodiments, the fluorescence emission wavelength of the quantum dots is preferably 470 nm to 480 nm.
  • the aforementioned fluorescence emission wavelength is the wavelength at which the peak of the photoluminescence (PL) spectrum of a sample is measured at the maximum.
  • This application also provides a method for preparing the aforementioned quantum dots, including the steps:
  • uniform speed is not an absolute uniform speed, and the amount of substances added to the precursor twice adjacently may have an allowable error within ⁇ 10%.
  • the preparation process of the inner core includes: mixing the second zinc precursor, the first selenium precursor, the second cadmium precursor, and the solvent, and reacting at a second temperature to obtain the first zinc-containing precursor.
  • the solution of alloy quantum dots uses the first alloy quantum dots to be purified as the core.
  • the second zinc precursor includes a long-chain fatty acid zinc with a carbon chain greater than or equal to 12.
  • the second zinc precursor may include short-chain fatty acid zinc with a carbon chain less than or equal to 8 and long-chain fatty acids with a carbon chain greater than or equal to 12, wherein the short-chain fatty acid zinc with a carbon chain of less than or equal to 8 includes zinc formate.
  • Long-chain fatty acids with a carbon chain greater than or equal to 12 include oleic acid and stearic acid. , At least one of isostearic acid, the two react to form a long-chain fatty acid zinc with a carbon chain greater than or equal to 12.
  • the first selenium precursor includes Se-ODE (octadecene-selenium), Se-TOP (selenium-trioctyl phosphine), Se-TBP (selenium-tributyl phosphine), Se-DPP At least one of (selenium-diphenylphosphine), but not limited thereto.
  • the second cadmium precursor is fatty acid cadmium with a carbon chain length greater than 12, including at least one of cadmium dodecanoate, cadmium myristate, cadmium stearate, and cadmium oleate, but is not limited thereto. .
  • the solvent may be, but not limited to, C6-C22 primary alkyl amines such as hexadecylamine, C6-C22 secondary alkyl amines such as dioctylamine, and C6-C40 alkyl tertiary amines such as Trioctylamine, nitrogen-containing heterocyclic compounds such as pyridine, C6-C40 olefins such as octadecene, C6-C40 aliphatic hydrocarbons such as hexadecane, octadecane or squalane, and C6-C30 alkyl Substituted aromatic hydrocarbons such as phenyldodecane, phenyltetradecane or phenylhexadecane, phosphines substituted by C6-C22 alkyl groups such as trioctylphosphine, phosphines substituted by C6-C22 alkyl groups
  • the second temperature is between 280°C and 310°C.
  • the reaction at the second temperature after the reaction at the second temperature, it further includes adding a second selenium precursor and reacting at the third temperature to obtain a solution containing the first alloy quantum dots.
  • the second selenium precursor can completely dissolve the unreacted first selenium precursor, and increase the content of selenium in the mixed solution to avoid the fluorescence emission wavelength of the obtained CdZnSe quantum dots from exceeding the range of blue light.
  • the third temperature may be the same as or different from the above-mentioned second temperature, and the third temperature is 300°C to 315°C. In a preferred embodiment, the third temperature is 310°C. In the above-mentioned temperature range, the CdZnSe quantum dots can be alloyed completely at high temperature, and the quantum yield of the CdZnSe quantum dots can be improved.
  • the second selenium precursor contains organic phosphines, which can quickly dissolve unreacted selenium element.
  • the second selenium precursor includes at least one of Se-TOP, Se-TBP, and Se-DPP, but Not limited to this.
  • the content of Cd element affects the emission wavelength of CdZnSe quantum dots, in order to make the emission wavelength of CdZnSe quantum dots 460nm ⁇ 480nm or 470nm ⁇ 480nm.
  • the sum of the molar amount of the selenium element in the first selenium precursor and the second selenium precursor is 0.5 mmol ⁇ 1.5 mmol
  • the cadmium element in the second cadmium precursor and the first selenium precursor and The molar ratio of the sum of the molar amounts of the selenium element in the second selenium precursor is less than or equal to 0.48:1.
  • the average particle size of the CdZnSe quantum dots is 3.0 nm to 5.5 nm.
  • the preparation process of the inner core further includes:
  • step (1) of the core preparation process the solution containing the first alloy quantum dots synthesized by the solution method is directly used as the first intermediate solution, which not only can omit the purification step of the first alloy quantum dots as the core raw material, but also simplifies the operation. Increasing production efficiency can also prevent the bare first alloy quantum dot core material from being slowly oxidized by air, thereby reducing internal defects of the quantum dots.
  • step (2) of the core preparation process the short-chain fatty acid zinc and the long-chain fatty acid are mixed and reacted at the fourth temperature, the long-chain fatty acid will react with the short-chain fatty acid zinc, specifically the replacement of the long-chain fatty acid Short-chain fatty acid roots in short-chain fatty acid zinc form long-chain fatty acid zinc.
  • the long-chain fatty acid zinc exists in the solution as the precursor of the Zn element in the quantum dot core, and the replaced short-chain fatty acid roots will form short-chain fatty acids such as formic acid, acetic acid, propionic acid, butyric acid, etc., which are used for decomposition Oxidation products on the surface of quantum dots to reduce internal defects of quantum dots.
  • the above-mentioned short-chain fatty acid zinc includes at least one of zinc formate, zinc acetate, zinc propionate, and zinc butyrate, but not limited thereto.
  • the short-chain fatty acid zinc is zinc formate, zinc acetate, and propionic acid.
  • the aforementioned long-chain fatty acid includes at least one of oleic acid, stearic acid, and isostearic acid, but is not limited thereto.
  • each short-chain fatty acid zinc contains two short-chain fatty acid roots.
  • the above-mentioned long-chain fatty acid and the above-mentioned short-chain fatty acid The molar ratio of chain fatty acid zinc is greater than or equal to 2:1. In some embodiments, the molar ratio of the aforementioned long-chain fatty acid to the aforementioned short-chain fatty acid zinc is 2:1 to 4:1.
  • the fourth temperature needs to be greater than the boiling point of the short-chain fatty acid.
  • the fourth temperature is 100°C to 240°C. Adjust according to the boiling point of short-chain fatty acids.
  • step (3) of the core preparation process when reacting at the fifth temperature, the long-chain fatty acid zinc present in the second intermediate solution reacts with the third selenium precursor to continue to grow on the surface of the first alloy quantum dots, Obtain the second alloy quantum dots.
  • the fifth temperature is between 280°C and 310°C.
  • steps (2) and (3) of the core preparation process are repeated at least n times for continued growth.
  • the n+1th alloy quantum dot solution replaces the core preparation process (
  • the first intermediate solution in 1) is used to obtain a solution containing the n+2th alloy quantum dots, and the n+2th alloy quantum dots are purified as the inner core, and n is a positive integer greater than or equal to 1.
  • the solution of the i+1th alloy quantum dots replaces the first intermediate solution in step (1) of the core preparation process to obtain a solution containing the i+2th alloy quantum dots ,
  • the i+2th alloy quantum dot is purified as the core, and i is a positive integer less than n.
  • the solution of the second alloy quantum dots replaces the first intermediate solution in step (1) of the core preparation process to obtain a solution containing the third alloy quantum dots, and the third alloy quantum dots
  • the alloy quantum dots are purified as the core; when n is 2, the solution of the second alloy quantum dots replaces the first intermediate solution in step (1) in the first repetition to obtain a solution containing the third alloy quantum dots.
  • the solution of the third alloy quantum dots continues to replace the first intermediate solution in step (1) to obtain a solution containing the fourth alloy quantum dots, and the fourth alloy quantum dots are purified as the core.
  • n is greater than 2, it is similar to the above repeated process, and will not be expanded one by one here.
  • the CdZnSe quantum dot core can be obtained in multiple consecutive preparations, which can reduce the amount of short-chain fatty acid zinc used during the preparation and ensure the reaction
  • the short-chain fatty acid zinc in the system will not be excessive, which can effectively avoid the excessive accumulation of long-chain fatty acid zinc formed, reduce the probability of long-chain fatty acid zinc decomposing at high temperature to generate oxidation products, and minimize the internal defects of CdZnSe quantum dots.
  • short-chain fatty acid zinc and long-chain fatty acid are added in situ, small molecular acids such as formic acid, acetic acid, propionic acid, butyric acid will be generated, which can continuously decompose or etch away oxidation products such as ZnO or ZnSeO 3 , Thereby further decompose and eliminate the internal defects of the quantum dots, and improve the quantum yield of the quantum dots.
  • the amount of added short-chain fatty acid zinc and long-chain fatty acid can be the same or different each time step (2) and step (3) of the core preparation process are repeated.
  • the added short-chain fatty acid zinc The types of the long-chain fatty acids may be the same or different.
  • step (2) and step (3) of the core preparation process can be repeated once or multiple times to obtain a CdZnSe quantum dot core with an average particle diameter of 3 nm-10 nm.
  • the thickness of the growth is less than or equal to 1.5 nm.
  • the thickness of each repetition of the growth is less than or equal to 1.5nm.
  • the thickness of the alloy quantum dots that continue to grow is not greater than each time step (2) and step (3) of the core preparation process are repeated 1.5nm, in some embodiments, the molar concentration of selenium in the third selenium precursor is 0.5mmol/mL-4mmol/mL, and the selenium in the third selenium precursor is different from the zinc in the second intermediate solution.
  • the molar ratio is 1:2 to 2:1.
  • the above-mentioned molar concentration of selenium in the third selenium precursor refers to the molar concentration of selenium in the third selenium precursor before the third selenium precursor is added to the second intermediate solution.
  • the molar ratio of the selenium element in the third selenium precursor to the zinc element in the second intermediate solution It is 1:1.
  • step S2 because of the high activity of Cd element, element S will preferentially react with Cd element at high temperature. Therefore, in order to ensure the uniformity of Cd element in the CdZnSe shell layer, the first cadmium precursor needs to be added to the first precursor at a uniform rate. In solution. Further, it is preferable to add the first cadmium precursor and the first sulfur precursor to the first precursor solution at a uniform rate separately or together.
  • an excess of the first zinc precursor exists in the first precursor solution, and when the first cadmium precursor is added to the first precursor solution, the excess Zn element in the first precursor solution can inhibit the activity of Cd element , To ensure the uniform growth of the CdZnS shell layer.
  • the first cadmium precursor and the first sulfur precursor may be added to the first precursor solution at a uniform rate.
  • the first zinc precursor includes long-chain fatty acid zinc with a carbon chain greater than or equal to 12.
  • the first zinc precursor may include short-chain fatty acid zinc with a carbon chain less than or equal to 8 and long-chain fatty acids with a carbon chain greater than or equal to 12, wherein the short-chain fatty acid zinc with a carbon chain of less than or equal to 8 includes zinc formate, At least one of zinc acetate, zinc propionate, and zinc butyrate, but not limited thereto, preferably at least one of zinc formate, zinc acetate, and zinc propionate.
  • Long-chain fatty acids with a carbon chain greater than or equal to 12 include oleic acid At least one of, stearic acid, and isostearic acid, but not limited to this, the two react to form a long-chain fatty acid zinc with a carbon chain greater than or equal to 12.
  • the inner core is mixed with short-chain fatty acid zinc, long-chain fatty acid, and solvent, and the temperature is raised to 150°C to 240°C to react to form the long-chain fatty acid zinc precursor, and then fatty amine is added to form the first precursor. Solution.
  • the fatty amine is a fatty amine with a carbon chain greater than or equal to 8, including at least one of octaamine, dodecylamine, oleylamine, and octadecylamine, but is not limited thereto.
  • the first sulfur precursor is elemental sulfur soluble in alkyl phosphine, including at least one of S-TBP, S-TOP, and S-DPP, but is not limited thereto.
  • the first temperature is between 290°C and 310°C, preferably 300°C.
  • the Cd element, S element and Zn element in the second precursor solution react, It is beneficial to coat the surface of the inner core to form a homogeneous CdZnS shell layer.
  • the carbon chain in the above-mentioned short-chain fatty acid zinc with a carbon chain less than or equal to 8 is the number of carbons in the fatty acid zinc main chain
  • the carbon chain in the long-chain fatty acid with a carbon chain greater than or equal to 12 is the number of carbons in the fatty acid main chain.
  • the carbon chain in the fatty amine greater than or equal to 8 is the carbon number of the main chain of the fatty amine.
  • This application also provides another method for preparing the aforementioned quantum dots, including the steps:
  • the second precursor solution is reacted at the first temperature to coat the surface of the core to form a shell layer to obtain quantum dots.
  • the fatty alcohol is selected from fatty alcohols having a carbon chain length of 12-30.
  • the fatty alcohol is selected from one or more of dodecanol, cetyl alcohol, stearyl alcohol, behenyl alcohol, and triacontanol, but is not limited thereto.
  • the preparation process of the inner core includes: mixing the second zinc precursor, the first selenium precursor, the second cadmium precursor, and the solvent, and reacting at a second temperature to obtain the first alloy quantum dots Solution, the first alloy quantum dots are purified as the core.
  • reaction at the second temperature after the reaction at the second temperature, it further includes adding a second selenium precursor and reacting at the third temperature to obtain a solution containing the first alloy quantum dots.
  • the preparation process of the inner core further includes: (1) using a solution containing the first alloy quantum dots as the first intermediate solution; (2) combining the first intermediate solution with short-chain fatty acids with a carbon chain length of 8 or less Zn and long-chain fatty acids with a carbon chain length greater than or equal to 12 are mixed, and reacted at the fourth temperature to obtain a second intermediate solution; (3) The second intermediate solution is mixed with the third selenium precursor and kept at the fifth temperature Reacting to make the first alloy quantum dots continue to grow to obtain a solution containing the second alloy quantum dots; (4) purifying the second alloy quantum dots as the core.
  • steps (2) and (3) of the core preparation process are repeated at least n times for continued growth.
  • the solution of the i+1th alloy quantum dot replaces the first step in step (1).
  • An intermediate solution to obtain a solution containing the i+2th alloy quantum dots, the i+2th alloy quantum dots are purified as the core, n is a positive integer greater than or equal to 1, and i is a positive integer less than or equal to n.
  • the molar ratio of the long-chain fatty acid to the zinc short-chain fatty acid is greater than or equal to 2:1.
  • the molar ratio of the long-chain fatty acid to the zinc short-chain fatty acid is 2:1 to 4:1.
  • the molar ratio of the selenium element in the third selenium precursor to the zinc element in the second intermediate solution is 1:2 to 2:1, and the molar concentration of the selenium element in the third selenium precursor is 0.5 mmol /mL ⁇ 4mmol/mL.
  • the thickness of the growth is less than or equal to 1.5 nm; and, when the n+1th alloy quantum dots continue to grow into the n+2th alloy quantum dots, The thickness of each repetition is less than or equal to 1.5nm.
  • the present application also provides a quantum dot composition, which includes any of the foregoing quantum dots or a quantum dot prepared by any of the foregoing preparation methods.
  • the quantum dot composition can be optical materials, color conversion materials, inks, coatings, labeling agents, luminescent materials, and the like.
  • the quantum dot composition includes glue, polymer colloid, or solvent.
  • the amount of host material present in the quantum dot composition may be about 80 to about 99.5 weight percent.
  • particularly useful host materials include, but are not limited to, polymers, oligomers, monomers, resins, adhesives, glasses, metal oxides, and other non-polymer materials.
  • Preferred host materials include polymeric and non-polymeric materials that are at least partially transparent to a preselected wavelength of light, and preferably completely transparent.
  • the present application also provides an optoelectronic device, which includes any of the foregoing quantum dots or a quantum dot prepared by any of the foregoing preparation methods.
  • the optoelectronic device may be a quantum dot light conversion film, a quantum dot color film and a device used in combination with an LED, a quantum dot light-emitting diode, and the like.
  • the optoelectronic device is a quantum dot light emitting diode.
  • the quantum dot light emitting diode reaches the highest external quantum efficiency, the required operating current density is 5mA/cm 2 ⁇ 20mA/cm 2 , and the highest external quantum efficiency is 9.6% ⁇ 12.6 %.
  • the EQE reaches its maximum value at a low operating current density of 5 mA/cm 2 to 20 mA/cm 2. Therefore, due to the lower operating current density required by the optoelectronic device, the life of the optoelectronic device is longer, and the actual commercialization requirements of blue QLEDs can be more satisfied.
  • quantum dot its preparation method, quantum dot composition, and optoelectronic device will be further described through the following specific examples.
  • CdZnSe quantum dot solution Take 5.0 mL of the above CdZnSe quantum dot solution, 10 mmol zinc acetate, 25 mmol oleic acid, and 10 g ODE and mix, under the protection of nitrogen, the temperature is raised to 150°C for 30 min. Then add 1mL oleylamine, heat up to 300°C, start to add dropwise Cd-ODE-S-TBP mixed solution (9mL 0.1mmol/mL cadmium oleate ODE solution mixed with 3mL2mmol/mL S-TBP, Cd element and S element The molar ratio is 0.15:1), and the dropping rate is 4mL/h.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 4nm, the thickness of the CdZnS shell is 6nm, and the molar ratio of Cd to S in the shell is 0.15:1.
  • the temperature is lowered to room temperature, and the CdZnSe/CdZnS quantum dots are purified.
  • the average particle size of the CdZnSe core is 5.5nm
  • the thickness of the CdZnS shell is 3nm
  • the molar ratio of Cd to S in the shell is 0.2:1 .
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 7nm, the thickness of the CdZnS shell layer is 3nm, and the molar ratio of Cd element to S element in the shell layer is 0.15:1.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 7nm, the thickness of the CdZnS shell layer is 6nm, and the molar ratio of Cd element to S element in the shell layer is 0.25:1.
  • the above solution was cooled to room temperature, under the protection of nitrogen atmosphere, 3mmol zinc acetate and 7.5mmol oleic acid were added, then the temperature was raised to 180°C for 30 minutes with nitrogen, 1.5mL 2mmol/mL Se-TBP solution was added, and the temperature was raised to 310°C and reacted for 30 minutes.
  • CdZnSe quantum dot solution Take 5.0 mL of the above CdZnSe quantum dot solution, 10 mmol zinc acetate, 25 mmol oleic acid, and 10 g ODE and mix, under the protection of nitrogen, the temperature is raised to 150°C for 30 min. Then add 1mL oleylamine, heat up to 300°C, start to add dropwise Cd-ODE-S-TBP mixed solution (9mL 0.2mmol/mL cadmium oleate ODE solution and 3mL2mmol/mL S-TBP mixed, Cd element and S element The molar ratio is 0.3:1), and the dropping rate is 5mL/h.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 8nm, the thickness of the CdZnS shell layer is 4nm, and the molar ratio of Cd element to S element in the shell layer is 0.3:1.
  • the above solution was cooled to room temperature, under the protection of nitrogen atmosphere, 3mmol zinc formate and 7.5mmol dodecanoic acid were added, then the temperature was raised to 150°C for 30 minutes with nitrogen, 1.5mL 2mmol/mL Se-TBP solution was added, and the temperature was raised to 310°C for 30 minutes.
  • the above solution was cooled to room temperature, and under the protection of nitrogen atmosphere, 4mmol zinc propionate and 10mmol oleic acid were added, then the temperature was raised to 180°C and nitrogen gas was introduced for 30min, 2mL 2mmol/mL Se-TBP solution was added, and the reaction temperature was raised to 310°C for 30min.
  • the above solution was cooled to room temperature, under the protection of nitrogen atmosphere, 5mmol zinc octoate and 12.5mmol stearic acid were added, then the temperature was raised to 240°C and nitrogen gas was introduced for 30min, and 2.5mL 2mmol/mL Se-TOP solution was added, and the temperature was raised to 310°C and reacted for 30min.
  • the CdZnSe quantum dots with an average particle diameter of 10 nm are obtained by purification, and they are dissolved in 10 mL of octadecene for use.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 10nm, the thickness of the CdZnS shell layer is 3nm, and the molar ratio of Cd element to S element in the shell layer is 0.4:1.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots.
  • the average particle size of the CdZnSe core is 3nm
  • the thickness of the CdZnS shell is 10nm
  • the molar ratio of Cd to S in the shell is 0.15:1.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 3.5nm, the thickness of the CdZnS shell layer is 4.5nm, and the molar ratio of Cd element to S element in the shell layer is 0.15: 1.
  • Example 3 The only difference between this example and Example 3 is that in the reaction step of coating the CdZnS shell layer, "addition of 1 mL of oleylamine” is replaced with “addition of 1 g of stearyl alcohol”.
  • Example 6 The only difference between this example and Example 6 is that in the reaction step of coating the CdZnS shell layer, "addition of 1 mL of oleylamine” is replaced with “addition of 0.8 g of cetyl alcohol”.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 7nm, the thickness of the CdZnS shell layer is 3nm, and the molar ratio of Cd element to S element in the shell layer is 0.125:1.
  • CdZnSe quantum dot solution Take 5.0 mL of the above CdZnSe quantum dot solution, 10 mmol zinc acetate, 25 mmol oleic acid, and 10 g ODE and mix, under the protection of nitrogen, the temperature is raised to 150°C for 30 min. Then add 1mL oleylamine, heat up to 300°C, start to add dropwise Cd-ODE-S-TBP mixed solution (8mL 0.05mmol/mL cadmium oleate ODE solution mixed with 2mL 2mmol/mL S-TBP, Cd element and S element The molar ratio is 0.1:1), and the dropping rate is 5mL/h.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 7nm, the thickness of the CdZnS shell layer is 3nm, and the molar ratio of Cd element to S element in the shell layer is 0.1:1.
  • CdZnSe/ZnS quantum dots are purified to obtain CdZnSe/ZnS quantum dots, wherein the average particle size of the CdZnSe core is 7 nm, and the thickness of the ZnS shell layer is 3 nm.
  • CdZnSe/CdZnS quantum dots are purified to obtain CdZnSe/CdZnS quantum dots, wherein the average particle size of the CdZnSe core is 7nm, the thickness of the CdZnS shell layer is 3nm, and the molar ratio of Cd element to S element in the shell layer is 0.5:1.
  • the quantum dots of Examples 1 to 10 and Comparative Examples 1 to 4 were made into optoelectronic devices.
  • the structure of the optoelectronic devices was ITO/PEDOTS:PSS/TFB/Quantum dots/ZnMgO/Al.
  • the specific preparation methods are as follows:
  • ITO glass sheet on the back into a glass dish filled with ethanol solution, and wipe the ITO surface clean with a cotton swab. After sonicating each with acetone, deionized water, and ethanol for 10 minutes, they were blown dry with a nitrogen gun. Finally, place the cleaned ITO glass sheet in oxygen plasma and continue cleaning for 10 minutes.
  • the cleaned ITO glass sheet was spin-coated with PEDOTS:PSS in the air, the rotation speed was 3000r/min, and the spin coating time was 45 seconds. After the spin coating is completed, it is placed in the air for annealing, the annealing temperature is 150°C, and the annealing time is 30 minutes. After the annealing is completed, the film is quickly transferred to a glove box in a nitrogen atmosphere.
  • the optical concentration at 350nm is 30-40, dissolved in octane solvent.
  • the spin-coating speed is 2000r/min, and the spin-coating time is 45 seconds.
  • the next layer can be spin coated without annealing.
  • MgZnO nanocrystals (30mg/mL, ethanol solution): spin-coated the MgZnO nanocrystal solution on the ITO/PEDOTS:PSS/TFB/Quantum dots at a rotation speed of 2000r/min for 45 seconds.
  • the evaporation rate is controlled at Within the range, the evaporation rate after 10nm is increased to about.
  • the thickness of the aluminum electrode is 100 nm.
  • the Keithley 2400 was used to measure the current density-voltage curve of the quantum dot light-emitting device, and the integrating sphere (FOIS-1) combined with the Ocean Optics spectrometer (QE-pro) was used to measure the brightness of the photoelectric device.
  • the external quantum efficiency characterizes the ratio between the number of photons emitted by the optoelectronic device and the number of electrons injected into the device in the observation direction. It is an important parameter that characterizes the luminous efficiency of the optoelectronic device. The higher the external quantum efficiency, the higher the luminous efficiency of the device.
  • EL refers to the emission peak wavelength of the optoelectronic device
  • EQE(ave) refers to the average external quantum efficiency of the optoelectronic device
  • T50 refers to the brightness of the optoelectronic device reduced to 50 of the initial brightness under the lighting condition of 100cd/m 2 % Required aging time.
  • EQE max current density refers to the working current density when the EQE of the optoelectronic device reaches its maximum.
  • Figures 1 to 12 show the current density curves of the various examples and comparative examples, from which you can see the device’s The highest EQE and corresponding EQE max current density.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Nanotechnology (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Computer Hardware Design (AREA)
  • Optics & Photonics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Luminescent Compositions (AREA)

Abstract

本申请涉及一种量子点及其制备方法、量子点组合物、光电器件；量子点包括内核和包覆于内核的壳层，内核的材料为CdZnSe，壳层的材料为CdZnS，其中，壳层中Cd元素与S元素的摩尔比为0.15:1～0.4:1。该量子点的能级结构更加匹配空穴传输层和电子传输层，载流子注入势垒较低，应用于光电器件后，在5～20mA/cm 2的工作电流密度下，EQE即达到最大值，光电器件寿命更长，更能够满足商业化需求。

Description

量子点及其制备方法、量子点组合物、光电器件 技术领域
本申请涉及量子点技术领域，特别是涉及量子点及其制备方法、量子点组合物、光电器件。
背景技术
目前，CdZnS/ZnS、CdZnSeS/ZnS、ZnCdSe/ZnS等蓝光量子点的器件外量子效率(EQE)已经达到10％以上，最大亮度也超过10000cd/m 2。但是，这类蓝光量子点的外层均包覆有较厚的ZnS壳层，导致蓝光量子点的最高占据分子轨道(HOMO)能级较深(即绝对值较大)，最低未占分子轨道(LUMO)能级较高，不利于载流子的有效注入，使得这类蓝光量子点的光电器件的寿命一般不会超过1000小时，远远无法满足商业化的最低要求。
另外，现有技术中提出了在ZnCdSe外包覆大约7nm厚的ZnSe壳层，可以有效提升蓝光量子点的HOMO能级，缩短其与空穴传输层TFB材料的能级差距，使得这类蓝光量子点的光电器件在100cd/m 2的点亮条件下达到了7000h的水平，比包覆ZnS壳层的量子点的寿命有了显著提升。但是，这类蓝光量子点的光电器件要在10000cd/m 2的点亮条件下，外量子点效率(EQE)才能达到最高值，而此时光电器件的工作电流密度为88mA/cm 2。所以，这类蓝光量子点的光电器件在50cd/m 2～200cd/m 2的实际商业化需求亮度下，EQE衰减到3％，外量子效率极低，远远达不到商业化需求。
发明内容
基于此，有必要针对上述问题，提供一种量子点及其制备方法、量子点组合物、光电器件；上述量子点的能级结构更加匹配空穴传输层和电子传输层，载流子注入势垒较低，应用于光电器件后，在5mA/cm 2～20mA/cm 2的工作电流密度下，EQE即达到最大值，光电器件寿命更长，更满足实际商业化需求。
本申请的一方面，提供一种量子点，包括内核和包覆上述内核的壳层，上述内核的材料为CdZnSe，上述壳层的材料为CdZnS，其中，上述壳层中Cd元素与S元素的摩尔比为0.15:1～0.4:1。
进一步地，上述内核的平均粒径为3nm～10nm，上述壳层的厚度为3nm～10nm。
进一步地，上述内核的平均粒径为5nm～9nm，上述壳层的厚度为3nm～5nm。
进一步地，上述量子点的荧光发射波长为460nm～480nm。
进一步地，上述量子点的荧光发射波长为470nm～480nm。
本申请的另一方面，提供一种如上述的量子点的制备方法，包括步骤：制备内核；将上述内核与第一锌前驱体、脂肪胺、溶剂混合形成第一前驱体溶液，再将第一镉前驱体和第一硫前驱体分别或共同匀速加入至上述第一前驱体溶液以形成第二前驱体溶液，上述第二前驱体溶液中Cd元素与S元素的摩尔比为0.15:1～0.4:1；将上述第二前驱体溶液在第一温度下进行反应，以在上述内核的表面包覆形成壳层，得到量子点。
进一步地，上述内核的制备过程包括：将第二锌前驱体、第一硒前驱体、第二镉前驱体、溶剂混合，并在第二温度下反应，得到含第一合金量子点的溶液，将上述第一合金量子点提纯作为上述内核。
进一步地，在第二温度下反应之后，还包括加入第二硒前驱体，并在第三温度下反应，得到上述含第一合金量子点的溶液。
进一步地，上述内核的制备过程还包括：
(1)将上述含第一合金量子点的溶液作为第一中间溶液；
(2)将上述第一中间溶液与碳链长度小于等于8的短链脂肪酸锌、碳链长度大于等于12的长链脂肪酸混合，并在第四温度下反应，得到第二中间溶液；
(3)将上述第二中间溶液与第三硒前驱体混合，并在第五温度下反应，以使上述第一合金量子点继续生长，得到含第二合金量子点的溶液；
(4)将上述第二合金量子点提纯作为上述内核。
进一步地，至少重复n次步骤(2)和(3)进行继续生长，第n次重复时，第n+1合金量子点的溶液替代步骤(1)中的上述第一中间溶液，以得到含第n+2合金量子点的溶液，将上述第n+2合金量子点提纯作为上述内核，n为大于等于1正整数。
进一步地，上述长链脂肪酸与上述短链脂肪酸锌的摩尔比大于等于2:1。
进一步地，上述长链脂肪酸与上述短链脂肪酸锌的摩尔比为2:1～4:1。
进一步地，上述第三硒前驱体中的硒元素与上述第二中间溶液中的锌元素的摩尔比为1:2～2:1，上述第三硒前驱体中硒元素的摩尔浓度为0.5mmol/mL～4mmol/mL。
进一步地，上述第一合金量子点继续生长成第二合金量子点时，生长的厚度小于等于1.5nm；以及，上述第n+1合金量子点继续生长成第n+2合金量子点时，每重复一次所生长的厚度均小于等于1.5nm。
进一步地，第i次重复时，第i+1合金量子点的溶液替代步骤(1)中的上述第一中间溶液，以得到含第i+2合金量子点的溶液，将上述第i+2合金量子点提纯作为上述内核，上述i为小于上述n的正整数。
本申请的又一方面，提供一种如上述的量子点的制备方法，包括步骤：
制备内核；将上述内核与第一锌前驱体、脂肪醇、溶剂混合形成第一前驱体溶液，再将第一镉前驱体和第一硫前驱体分别或共同匀速加入至上述第一前驱体溶液以形成第二前驱体溶液，上述第二前驱体溶液中Cd元素与S元素的摩尔比为0.15:1～0.4:1；将上述第二前驱体溶液在第一温度下进行反应，以在上述内核的表面包覆形成壳层，得到量子点。
进一步地，上述脂肪醇选自碳链长度为12～30的脂肪醇。
本申请的又一方面，提供一种量子点组合物，包括上述的量子点或包括上述的制备方法制备而成的量子点。
本申请的又一方面，提供一种光电器件，包括上述的量子点或包括上述的制备方法制备而成的量子点。
进一步地，上述光电器件为量子点发光二极管，上述量子点发光二极管达到最高外量子效率时所需工作电流密度为5mA/cm 2～20mA/cm 2，且上述最高外量子效率为9.6％～12.6％。
本申请的量子点采用浅HOMO能级的CdZnSe材料作为内核，更有利于空穴的注入，同时配以低LUMO能级的均质CdZnS材料作为壳层，且壳层中Cd元素与S元素的摩尔比为0.15:1～0.4:1，具有较好的能级结构，更加有利于电子的注入，从而，使得本申请的量子点的载流子注入势垒较低，更有利于载流子的注入。
进而，将本申请的量子点应用于光电器件后，在5mA/cm 2～20mA/cm 2的低工作电流密度下，EQE即达到最大值，且EQE最大值可以达到9.6％～12.6％。同时，因光电器件所需要的工作电流密度较低，使得该光电器件的寿命更长，更容易满足蓝光QLED的实际商业化需求。
附图说明
图1为实施例1的量子点发光二极管的电流密度-EQE曲线图；
图2为实施例2的量子点发光二极管的电流密度-EQE曲线图；
图3为实施例3的量子点发光二极管的电流密度-EQE曲线图；
图4为实施例4的量子点发光二极管的电流密度-EQE曲线图；
图5为实施例5的量子点发光二极管的电流密度-EQE曲线图；
图6为实施例6的量子点发光二极管的电流密度-EQE曲线图；
图7为实施例7的量子点发光二极管的电流密度-EQE曲线图；
图8为实施例8的量子点发光二极管的电流密度-EQE曲线图；
图9为对比例1的量子点发光二极管的电流密度-EQE曲线图；
图10为对比例2的量子点发光二极管的电流密度-EQE曲线图；
图11为对比例3的量子点发光二极管的电流密度-EQE曲线图；
图12为对比例4的量子点发光二极管的电流密度-EQE曲线图。
具体实施方式
以下将对本申请提供的量子点及其制备方法、量子点组合物、光电器件作进一步说明。
需要说明的是，本申请的说明书和权利要求书中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的本申请的实施例。此外，术语“包括”以及它的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产 品或设备固有的其它步骤或单元。
本申请提供的量子点的荧光发射波长为460nm～480nm，优选为470nm～480nm，为蓝光量子点。应用该量子点的光电器件在5mA/cm 2～20mA/cm 2的工作电流密度范围内，EQE即达到最大值，100cd/m 2点亮条件下T50寿命大于等于10000h，是一种低工作电流密度条件下，兼具高发光效率、高寿命的光电器件。
本申请的申请人经过长期而深入的研究发现，现有蓝光量子点无法达到商业化需求的本质原因是：蓝光量子点的能级结构与传输层材料差距过大，只有在较高的电场或电流密度下，载流子才可以顺利注入，器件亮度才能达到最高值，而在低电流密度工作条件下，载流子注入非常困难且不平衡，直接导致外量子效率严重衰减。
本申请提供一种能级结构更加匹配空穴传输层和电子传输层的量子点，包括内核和包覆内核的壳层，内核的材料为CdZnSe，壳层的材料为CdZnS，其中，壳层中Cd元素与S元素的摩尔比为0.15:1～0.4:1。
需要说明的是，本申请通过控制各前驱体的加入量和加入速度，且由于Cd元素的反应活性较高，反应结束时能够使原料中的Cd元素与S元素几乎全部被反应消耗，因此，上述壳层中Cd元素与S元素的摩尔比可以通过加入的原料(即下述第二前驱体溶液)中所含的Cd元素与S元素的摩尔比来确定，得到壳层中Cd元素与S元素的摩尔比约为0.15:1～0.4:1。在一些实施例中，壳层中Cd元素与S元素的摩尔比可以通过ICP检测分析得到。
具体地，CdZnS材料相对于ZnS而言，具有更低的LUMO能级，所以，以CdZnS材料作为壳层时，更有利于电子的注入。更重要的是，本申请的申请人经过长期而深入的研究发现，CdZnS材料作为壳层时，Cd元素的含量直接影响 CdZnS壳层的能带结构，而CdZnS壳层的能带结构，直接影响应用该量子点的光电器件的性能。
进一步地，当CdZnS壳层中Cd元素与S元素的摩尔比在0.15:1～0.4:1之间时，CdZnS壳层的能带结构较好，LUMO能级更低，更有利于电子的注入，且随着Cd元素的摩尔比的增大，效果更显著。
另外，CdZnSe材料相对于CdZnS材料、CdZnSeS材料而言，有更浅的HOMO能级，所以，以CdZnSe材料作为内核更有利于空穴的注入。
更重要的是，以CdZnSe材料作为内核，与具有上述元素摩尔比的CdZnS壳层具有更好的匹配关系。所以，以CdZnSe材料作为内核，配以上述元素摩尔比的CdZnS材料为壳层的量子点的载流子注入势垒较低，更有利于载流子的注入。应用于光电器件后，光电器件的电致发光效率更高、工作电流密度更低、寿命更长，更容易满足实际商业化需求。
在一些实施例中，上述壳层为均质CdZnS壳层，即壳层中Cd的分布均匀，以使壳层的能带结构更优。在评价壳层是否均质时，由于现有技术水平的限制，可以参考量子点制备方法的加料方式判断壳层是否为均质。
考虑到量子点应用于光电器件时的效果，在一些实施例中，上述内核的平均粒径为3nm～10nm，上述壳层的厚度为3nm～10nm。
在一些实施例中，上述内核的平均粒径为5nm～9nm，上述壳层的厚度为3nm～5nm。而对于相同粒径的内核，包覆不同厚度的壳层，使用效果相差不大，但是发射波长可能不同。
同一批制备的量子点可具有相对恒定的颗粒形状，平均粒径通过透射电子显微镜图像测定，但不限于此。当量子点具有球形形状时，上述量子点的平均粒径可为直径。当上述量子点为非球形形状的颗粒，上述量子点的平均粒径可 为由量子点的电子显微镜图像的二维面积计算得到的等效(相等)面积的圆的直径。上述壳层的厚度可通过测量包覆完成上述壳层后的量子点的平均粒径，然后减去相对应内核的平均粒径得到。
在一些实施例中，量子点的荧光发射波长为460nm～480nm，以保证量子点为蓝光量子点。在一些实施例中，量子点的荧光发射波长优选为470nm～480nm。
可以理解，上述荧光发射波长为对一个样品测光致发光(PL)光谱时峰值最大时的波长。
本申请还提供一种上述的量子点的制备方法，包括步骤：
S1，制备内核；
S2，将内核与第一锌前驱体、脂肪胺、溶剂混合形成第一前驱体溶液，再将第一镉前驱体和第一硫前驱体分别或共同匀速加入至第一前驱体溶液以形成第二前驱体溶液，第二前驱体溶液中Cd元素与S元素的摩尔比为0.15:1～0.4:1；
S3，将第二前驱体溶液在第一温度下进行反应，以在内核的表面包覆形成壳层，得到量子点。
需要说明的是，本申请中所提到的“匀速”并非绝对匀速，任意相邻两次加入前驱体的物质的量可以存在±10％范围以内的允许误差。
在一些实施例中，步骤S1中，内核的制备过程包括：将第二锌前驱体、第一硒前驱体、第二镉前驱体、溶剂混合，并在第二温度下反应，得到含第一合金量子点的溶液，将第一合金量子点提纯作为内核。
在一些实施例中，第二锌前驱体包括碳链大于等于12的长链脂肪酸锌。在一些实施例中，，第二锌前驱体可以包括碳链小于等于8的短链脂肪酸锌和碳链大于等于12的长链脂肪酸，其中，碳链小于等于8的短链脂肪酸锌包括甲酸锌、乙酸锌、丙酸锌、丁酸锌中的至少一种，优选为甲酸锌、乙酸锌、丙酸锌中的 至少一种，碳链大于等于12的长链脂肪酸包括油酸、硬脂酸、异硬脂酸中的至少一种，两者反应生成碳链大于等于12的长链脂肪酸锌。
在一些实施例中，第一硒前驱体包括Se-ODE(十八烯-硒)、Se-TOP(硒-三辛基膦)、Se-TBP(硒-三丁基膦)、Se-DPP(硒-二苯基膦)中的至少一种，但不限于此。
在一些实施例中，第二镉前驱体为碳链长度大于12的脂肪酸镉，包括十二酸镉、十四酸镉、硬脂酸镉、油酸镉中的至少一种，但不限于此。
在一些实施例中，溶剂可以是但不限于C6～C22的烷基伯胺如十六烷基胺，C6～C22的烷基仲胺如二辛基胺，C6～C40的烷基叔胺如三辛基胺，含氮杂环化合物如吡啶，C6～C40的烯烃如十八烯，C6～C40的脂族烃如十六烷、十八烷或角鲨烷，被C6～C30的烷基取代的芳族烃如苯基十二烷、苯基十四烷或苯基十六烷，被C6～C22的烷基取代的膦如三辛基膦，被C6～C22的烷基取代的膦氧化物如三辛基膦氧化物，C12～C22的芳族醚如苯醚、或苄醚，或其组合。壳层制备使用的溶剂和内核制备使用的溶剂可以相同或不同。
在一些实施例中，第二温度为280℃～310℃。
在一些实施例中，在第二温度下反应之后，还包括加入第二硒前驱体，并在第三温度下反应，得到含第一合金量子点的溶液。在该过程中，第二硒前驱体可以完全溶解未反应的第一硒前驱体，并增加混合液中硒元素的含量，避免得到的CdZnSe量子点的荧光发射波长超出蓝光的范围。
在一些实施例中，第三温度可以与上述第二温度相同或不同，第三温度为300℃～315℃。在一种优选的实施例中，第三温度为310℃。在上述温度范围内，可使CdZnSe量子点在高温下合金化完全，提高CdZnSe量子点的量子产率。
在一些实施例中，第二硒前驱体中含有有机膦，从而可以快速溶解未反应 的硒单质，第二硒前驱体包括Se-TOP、Se-TBP、Se-DPP中的至少一种，但不限于此。
在CdZnSe量子点中，Cd元素的含量影响CdZnSe量子点的发射波长，为了使CdZnSe量子点的发射波长为460nm～480nm或者470nm～480nm。在一些实施例中，第一硒前驱体和第二硒前驱体中的硒元素的摩尔量之和为0.5mmol～1.5mmol，且第二镉前驱体中的镉元素与第一硒前驱体和第二硒前驱体中的硒元素的摩尔量之和的摩尔比小于等于0.48:1。
在一些实施例中，CdZnSe量子点的平均粒径为3.0nm～5.5nm。
在一些实施例中，内核的制备过程还包括：
(1)将含第一合金量子点的溶液作为第一中间溶液；
(2)将第一中间溶液与碳链长度小于等于8的短链脂肪酸锌、碳链长度大于等于12的长链脂肪酸混合，并在第四温度下反应，得到第二中间溶液；
(3)将第二中间溶液与第三硒前驱体混合，并在第五温度下反应，以使第一合金量子点继续生长，得到含第二合金量子点的溶液；
(4)将第二合金量子点提纯作为内核。
内核的制备过程的步骤(1)中，直接将溶液法合成的含第一合金量子点的溶液作为第一中间溶液，不仅可以省略作为内核原料的第一合金量子点的提纯步骤，简化操作，提高生产效率，还可以避免裸露的第一合金量子点核原料被空气缓慢氧化，从而降低量子点的内部缺陷。
内核的制备过程的步骤(2)中，将短链脂肪酸锌和长链脂肪酸混合，并在第四温度下反应的过程中，长链脂肪酸会与短链脂肪酸锌反应，具体为长链脂肪酸置换短链脂肪酸锌中的短链脂肪酸根而形成长链脂肪酸锌。其中，长链脂肪酸锌作为量子点内核中Zn元素的前驱体存在于溶液中，而被置换出来的短链脂 肪酸根会形成甲酸、乙酸、丙酸、丁酸等短链脂肪酸，则用于分解量子点表面的氧化产物，以降低量子点的内部缺陷。
在一些实施例中，上述短链脂肪酸锌包括甲酸锌、乙酸锌、丙酸锌、丁酸锌中的至少一种，但不限于此，优选短链脂肪酸锌为甲酸锌、乙酸锌、丙酸锌中的至少一种。上述长链脂肪酸包括油酸、硬脂酸、异硬脂酸中的至少一种，但不限于此。
考虑到锌离子为二价离子，每个短链脂肪酸锌均含有两个短链脂肪酸根，为了充分将短链脂肪酸锌置换成长链脂肪酸锌，在一些实施例中，上述长链脂肪酸与上述短链脂肪酸锌的摩尔比大于等于2:1。在一些实施例中，上述长链脂肪酸与上述短链脂肪酸锌的摩尔比为2:1～4:1。
另外，为了使长链脂肪酸能够充分将短链脂肪酸锌置换为长链脂肪酸锌，第四温度需要大于短链脂肪酸的沸点，在一些实施例中，第四温度为100℃～240℃，具体可以依据短链脂肪酸的沸点进行调整。
内核的制备过程的步骤(3)中，在第五温度下反应时，存在于第二中间溶液中的长链脂肪酸锌与第三硒前驱体反应，在第一合金量子点的表面继续生长，得到第二合金量子点。
在一些实施例中，第五温度为280℃～310℃。
在一些实施例中，至少重复n次内核的制备过程的步骤(2)和(3)进行继续生长，第n次重复时，第n+1合金量子点的溶液替代内核的制备过程的步骤(1)中的所述第一中间溶液，以得到含第n+2合金量子点的溶液，将所述第n+2合金量子点提纯作为所述内核，n为大于等于1正整数。
在一些实施例中，第i次重复时，第i+1合金量子点的溶液替代内核的制备过程的步骤(1)中的第一中间溶液，以得到含第i+2合金量子点的溶液，将第i+2 合金量子点提纯作为内核，i为小于n的正整数。
即，当n为1时，第二合金量子点的溶液替代内核的制备过程的步骤(1)中的所述第一中间溶液，以得到含第三合金量子点的溶液，将所述第三合金量子点提纯作为内核；当n为2时，第1次重复时，第二合金量子点的溶液替代步骤(1)中的第一中间溶液，以得到含第三合金量子点的溶液，第2次重复时，第三合金量子点的溶液继续替代步骤(1)中的所述第一中间溶液，以得到含第四合金量子点的溶液，将第四合金量子点提纯作为所述内核。当n大于2时，与上述重复过程类似，此处不再一一展开。
从而，通过重复进行内核的制备过程的步骤(2)和步骤(3)，以多次连续制备的方式得到CdZnSe量子点内核，可减少制备时单次使用的短链脂肪酸锌的用量，保证反应体系中的短链脂肪酸锌不会过量，从而可以有效避免形成的长链脂肪酸锌的过量堆积，减少长链脂肪酸锌在高温下分解生成氧化产物的概率，最大限度降低CdZnSe量子点的内部缺陷。以及，每次原位补加短链脂肪酸锌和长链脂肪酸时，均会有甲酸、乙酸、丙酸、丁酸等小分子酸生成，可以持续分解或刻蚀掉ZnO或ZnSeO 3等氧化产物，从而进一步分解消除量子点的内部缺陷，提升量子点的量子产率。需要说明的是，每次重复内核的制备过程的步骤(2)和步骤(3)的过程中补加的短链脂肪酸锌和长链脂肪酸的量可以相同或者不同，补加的短链脂肪酸锌和长链脂肪酸的种类也可以相同或者不同。
在一些实施例中，内核的制备过程的步骤(2)和步骤(3)可以重复一次，也可以重复多次，以获得平均粒径为3nm～10nm的CdZnSe量子点内核。
在一些实施例中，第一合金量子点继续生长为第二合金量子点时，生长的厚度小于等于1.5nm。同样，第n+1合金量子点继续生长成第n+2合金量子点时，每重复一次所生长的厚度均小于等于1.5nm。
为了促进第三硒前驱体与第二中间溶液中的长链脂肪酸锌充分反应，且在每次重复内核的制备过程的步骤(2)和步骤(3)时合金量子点继续生长的厚度不大于1.5nm，在一些实施例中，第三硒前驱体中硒元素的摩尔浓度为0.5mmol/mL～4mmol/mL，且第三硒前驱体中的硒元素与第二中间溶液中的锌元素的摩尔比为1:2～2:1。上述第三硒前驱体中硒元素的摩尔浓度是指第三硒前驱体加入第二中间溶液之前第三硒前驱体中硒元素的摩尔浓度。
在一些实施例中，为了进一步避免长链脂肪酸锌过量而分解生成氧化产物，影响量子点的内部质量的提高，第三硒前驱体中的硒元素与第二中间溶液中的锌元素的摩尔比为1:1。
步骤S2中，因为Cd元素的活性较高，高温下S元素会优先与Cd元素反应，所以，为了保证CdZnSe壳层中Cd元素的均匀性，需要将第一镉前驱体匀速加入第一前驱体溶液中。进一步地，优选将第一镉前驱体和第一硫前驱体分别或共同匀速加入至第一前驱体溶液。
另外，过量的第一锌前驱体存在于第一前驱体溶液中，再向第一前驱体溶液中加入第一镉前驱体时，第一前驱体溶液中过量的Zn元素可以抑制Cd元素的活性，保证CdZnS壳层的均匀生长。
在一些实施例中，第一镉前驱体和第一硫前驱体可以分别匀速加入第一前驱体溶液中，为简化操作过程，优选将第一镉前驱体和第一硫前驱体混合后共同匀速加入第一前驱体溶液中。以第一硫前驱体的用量计，上述加入第一镉前驱体和第一硫前驱体的速度为2mmol/h～4mmol/h。
在一些实施例中，第一锌前驱体包括碳链大于等于12的长链脂肪酸锌。在一些实施例中，第一锌前驱体可以包括碳链小于等于8的短链脂肪酸锌和碳链大于等于12的长链脂肪酸，其中，碳链小于等于8的短链脂肪酸锌包括甲酸锌、 乙酸锌、丙酸锌、丁酸锌中的至少一种，但不限于此，优选为甲酸锌、乙酸锌、丙酸锌中的至少一种，碳链大于等于12的长链脂肪酸包括油酸、硬脂酸、异硬脂酸中的至少一种，但不限于此，两者反应生成碳链大于等于12的长链脂肪酸锌。
在一些实施例中，将内核与短链脂肪酸锌、长链脂肪酸、溶剂混合，升温到150℃～240℃反应，生成长链脂肪酸锌前驱体后，再加入脂肪胺，以形成第一前驱体溶液。
在一些实施例中，脂肪胺为碳链大于等于8的脂肪胺，包括八胺、十二胺、油胺、十八胺中的至少一种，但不限于此。第一硫前驱体为能够溶于烷基膦的单质硫，包括S-TBP、S-TOP、S-DPP中的至少一种，但不限于此。
在一些实施例中，步骤S3中，第一温度为290℃～310℃，优选为300℃，在上述第一温度范围下，第二前驱体溶液中的Cd元素、S元素与Zn元素反应，有利于在内核的表面包覆形成均质的CdZnS壳层。
可以理解，上述碳链小于等于8的短链脂肪酸锌中的碳链为脂肪酸锌主链的碳数量，碳链大于等于12的长链脂肪酸中的碳链为脂肪酸主链的碳数量，碳链大于等于8的脂肪胺中的碳链为脂肪胺主链的碳数量。
本申请还提供上述的量子点的另一种制备方法，包括步骤：
S1’，制备内核；
S2’，将内核与第一锌前驱体、脂肪醇、溶剂混合形成第一前驱体溶液，再将第一镉前驱体和第一硫前驱体分别或共同匀速加入至第一前驱体溶液以形成第二前驱体溶液，第二前驱体溶液中Cd元素与S元素的摩尔比为0.15:1～0.4:1；
S3’，将第二前驱体溶液在第一温度下进行反应，以在内核的表面包覆形成壳层，得到量子点。
在一些实施例中，脂肪醇选自碳链长度为12～30的脂肪醇。
在一些实施例中，脂肪醇选自十二烷醇、十六醇、十八醇、二十二醇和三十烷醇中的一种或多种，但不限于此。
在一些实施例中，内核的制备过程包括：将第二锌前驱体、第一硒前驱体、第二镉前驱体、溶剂混合，并在第二温度下反应，得到含第一合金量子点的溶液，将第一合金量子点提纯作为内核。
在一些实施例中，在第二温度下反应之后，还包括加入第二硒前驱体，并在第三温度下反应，得到含第一合金量子点的溶液。
在一些实施例中，内核的制备过程还包括：(1)将含第一合金量子点的溶液作为第一中间溶液；(2)将第一中间溶液与碳链长度小于等于8的短链脂肪酸锌、碳链长度大于等于12的长链脂肪酸混合，并在第四温度下反应，得到第二中间溶液；(3)将第二中间溶液与第三硒前驱体混合，并在第五温度下反应，以使第一合金量子点继续生长，得到含第二合金量子点的溶液；(4)将第二合金量子点提纯作为内核。
在一些实施例中，至少重复n次内核的制备过程的步骤(2)和(3)进行继续生长，第i次重复时，第i+1合金量子点的溶液替代步骤(1)中的第一中间溶液，以得到含第i+2合金量子点的溶液，将第i+2合金量子点提纯作为内核，n为大于等于1正整数，i为小于等于n的正整数。
在一些实施例中，长链脂肪酸与短链脂肪酸锌的摩尔比大于等于2:1。
在一些实施例中，长链脂肪酸与短链脂肪酸锌的摩尔比为2:1～4:1。
在一些实施例中，第三硒前驱体中的硒元素与第二中间溶液中的锌元素的摩尔比为1:2～2:1，第三硒前驱体中硒元素的摩尔浓度为0.5mmol/mL～4mmol/mL。
在一些实施例中，第一合金量子点继续生长成第二合金量子点时，生长的厚度小于等于1.5nm；以及，第n+1合金量子点继续生长成第n+2合金量子点时，每重复一次所生长的厚度均小于等于1.5nm。
本申请还提供一种量子点组合物，包括上述任一量子点或包括上述任一制备方法制备而成的量子点。量子点组合物可以为光学材料、颜色转换材料、油墨、涂料、标签剂、发光材料等。
在一些实施例中，量子点组合物包括胶水、高分子胶体、或者溶剂。
在一些实施例中，量子点组合物中主体材料的存在量可以为约80至约99.5重量百分比。具体有用的主体材料的实例包括但不限于聚合物、低聚物、单体、树脂、粘合剂、玻璃、金属氧化物、和其它非聚合物材料。优选的主体材料包括聚合和非聚合的材料，其对于光的预选波长，是至少部分透明的，以及优选完全透明的。
本申请还提供一种光电器件，包括上述任一量子点或包括上述任一制备方法制备而成的量子点。
在一些实施例中，光电器件可以是量子点光转化膜、量子点彩膜及其与LED结合使用的器件、量子点发光二极管等。
在一些实施例中，光电器件为量子点发光二极管，量子点发光二极管达到最高外量子效率时所需工作电流密度为5mA/cm 2～20mA/cm 2，且最高外量子效率为9.6％～12.6％。
因此，将本申请的量子点应用于光电器件后，在5mA/cm 2～20mA/cm 2的低工作电流密度下，EQE即达到最大值。从而，因光电器件所需要的工作电流密度较低，使得该光电器件的寿命更长，更能够满足蓝光QLED的实际商业化需求。
以下，将通过以下具体实施例对所述量子点及其制备方法、量子点组合物、光电器件做进一步的说明。
实施例1：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.2mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL 2mmol/mL的Se-TBP溶液，继续升温至310℃反应20min。提纯得到平均粒径为4.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(9mL 0.1mmol/mL油酸镉ODE溶液与3mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.15:1)，滴加速度4mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为4nm，CdZnS壳层的厚度为6nm，壳层中Cd元素与S元素的摩尔比为0.15:1。
实施例2：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.4mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL 2mmol/mL的Se-TBP溶液，继续升温至310℃反应60min。提纯得到平均粒径为5.5nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE 混合，氮气保护下，升温到150℃反应30min。然后补加1g十八胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(8mL 0.1mmol/mL油酸镉ODE溶液与2mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.2:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为5.5nm，CdZnS壳层的厚度为3nm，壳层中Cd元素与S元素的摩尔比为0.2:1。
实施例3：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.7mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL 2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol醋酸锌和7.5mmol油酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为7.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(6mL 0.1mmol/mL油酸镉ODE溶液与2mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.15:1)，滴加速度4mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为7nm，CdZnS壳层的厚度为3nm，壳层中Cd元素与S元素的摩尔比为0.15:1。
实施例4：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.4mL 0.2mmol/mL的硬脂酸镉ODE前驱体，升温至300℃，补加0.5mL2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol丙酸锌和7.5mmol硬脂酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为7.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加0.5mL八胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(7.5mL 0.2mmol/mL油酸镉ODE溶液与3mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.25:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为7nm，CdZnS壳层的厚度为6nm，壳层中Cd元素与S元素的摩尔比为0.25:1。
实施例5：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.4mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL 2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol乙酸锌和7.5mmol油酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min。
上述溶液降温到室温，氮气氛围保护下，加入2mmol丙酸锌和5mmol油酸，然后升温到180℃通氮气30min，补加1mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为8nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(9mL 0.2mmol/mL油酸镉ODE溶液与3mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.3:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为8nm，CdZnS壳层的厚度为4nm，壳层中Cd元素与S元素的摩尔比为0.3:1。
实施例6：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.3mL 0.2mmol/mL的十四酸镉ODE前驱体，升温至300℃，补加0.5mL2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol甲酸锌和7.5mmol十二酸，然后升温到150℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min。
上述溶液降温到室温，氮气氛围保护下，加入4mmol丙酸锌和10mmol油酸，然后升温到180℃通氮气30min，补加2mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min。
上述溶液降温到室温，氮气氛围保护下，加入5mmol辛酸锌和12.5mmol硬 脂酸，然后升温到240℃通氮气30min，补加2.5mL 2mmol/mL Se-TOP溶液，升温到310℃反应30min，提纯得到平均粒径为10nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(12mL 0.2mmol/mL油酸镉ODE溶液与3mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.4:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为10nm，CdZnS壳层的厚度为3nm，壳层中Cd元素与S元素的摩尔比为0.4:1。
实施例7：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.2mL 0.5mmol/mL的Se-ODE悬浮液和0.2mL 0.2mmol/mL的十二酸镉ODE前驱体，升温至300℃，补加0.5mL2mmol/mL的Se-TBP溶液，继续升温至310℃反应20min。提纯得到平均粒径为3.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1g十二胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(6mL 0.2mmol/mL油酸镉ODE溶液与4mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.15:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为3nm，CdZnS壳层的厚度为10nm，壳层中Cd元素与S元素的摩尔比为0.15:1。
实施例8：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.2mL 0.5mmol/mL的Se-ODE悬浮液和0.2mL 0.2mmol/mL的油酸镉ODE前驱体，升温至310℃，反应90min。提纯得到平均粒径为3.5nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(3mL 0.2mmol/mL油酸镉ODE溶液与2mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.15:1)，滴加速度2.5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为3.5nm，CdZnS壳层的厚度为4.5nm，壳层中Cd元素与S元素的摩尔比为0.15:1。
实施例9
本实施例与实施例3的区别仅在于：在包覆CdZnS壳层的反应步骤中，将“补加1mL油胺”替换为“补加1g十八醇”。
实施例10
本实施例与实施例6的区别仅在于：在包覆CdZnS壳层的反应步骤中，将“补加1mL油胺”替换为“补加0.8g十六醇”。
对比例1：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.7mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL 2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol醋酸锌和7.5mmol油酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为7.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(6.25mL 0.08mmol/mL油酸镉ODE溶液与2mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.125:1)，滴加速度4mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为7nm，CdZnS壳层的厚度为3nm，壳层中Cd元素与S元素的摩尔比为0.125:1。
对比例2：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.7mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol醋酸锌和7.5mmol油酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为7.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(8mL 0.05mmol/mL油酸镉ODE溶液与2mL 2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.1:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为7nm，CdZnS壳层的厚度为3nm，壳层中Cd元素与S元素的摩尔比为0.1:1。
对比例3：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.8mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL 2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol醋酸锌和7.5mmol油酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为7.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150摄氏度反应30min。然后补加1mL油胺，升温到300℃，开始滴加ODE-S-TBP混合溶液(6mL ODE与2mL 2mmol/mL S-TBP混合)，滴加速度4mL/h。反应完毕，降温到室温，提纯得到CdZnSe/ZnS量子点，其中，CdZnSe内核的平均粒径为7nm，ZnS壳层的厚度为3nm。
对比例4：
取2mmol碱式碳酸锌、1.4mL油酸、12g十八烯，氮气氛围保护下，升温至280℃形成澄清透明的溶液。然后依次注入1.0mL 0.5mmol/mL的Se-ODE悬浮液和0.7mL 0.2mmol/mL的油酸镉ODE前驱体，升温至300℃，补加0.5mL2mmol/mL的Se-TBP溶液，继续升温至310℃反应90min。
上述溶液降温到室温，氮气氛围保护下，加入3mmol醋酸锌和7.5mmol油酸，然后升温到180℃通氮气30min，补加1.5mL 2mmol/mL Se-TBP溶液，升温到310℃反应30min，提纯得到平均粒径为7.0nm的CdZnSe量子点，溶于10mL十八烯中备用。
取5.0mL上述的CdZnSe量子点溶液、10mmol乙酸锌、25mmol油酸和10g ODE混合，氮气保护下，升温到150℃反应30min。然后补加1mL油胺，升温到300℃，开始滴加Cd-ODE-S-TBP混合溶液(10mL 0.2mmol/mL油酸镉ODE溶液与2mL2mmol/mL S-TBP混合，Cd元素与S元素的摩尔比为0.5:1)，滴加速度5mL/h。反应完毕，降温到室温，提纯得到CdZnSe/CdZnS量子点，其中，CdZnSe内核的平均粒径为7nm，CdZnS壳层的厚度为3nm，壳层中Cd元素与S元素的摩尔比为0.5:1。
将实施例1～10和对比例1～4的量子点制成光电器件，光电器件的结构是ITO/PEDOTS:PSS/TFB/Quantum dots/ZnMgO/Al，具体制备方法如下：
1.ITO玻璃的清洗
将背面刻有编号的ITO玻璃片放入装有乙醇溶液的玻璃皿中，用棉签将ITO面擦洗干净。依次用丙酮、去离子水、乙醇各自超声10分钟后，用氮气枪吹干。最后，将清洗好的ITO玻璃片放置在氧气等离子体中继续清洗10分钟。
2.空穴注入层
将清洗完成的ITO玻璃片在空气中分别旋涂上PEDOTS:PSS，转速为3000r/min，旋涂时间为45秒。旋涂完成后放置在空气中退火，退火温度150℃，退火时间30分钟。退火完成后快速将片子转移至氮气氛围的手套箱中。
3.空穴传输层
将ITO/PEDOTS:PSS的片子继续旋涂上8～10mg/mL TFB的空穴传输层，转 速为2000r/min，旋涂时间为45秒。旋涂完成后在手套箱中退火，退火温度为150℃，退火时间为30分钟。
4.量子点发光层
核壳量子点，350nm处的光学浓度为30～40，溶解于八烷溶剂中。将ITO/PEDOTS:PSS/TFB的片子退火完成后继续旋涂量子点溶液，旋涂转速为2000r/min，旋涂时间为45秒。旋涂完成后无需退火即可旋涂下一层。
5.电子传输层
MgZnO纳米晶(30mg/mL，乙醇溶液)的旋涂：将ITO/PEDOTS:PSS/TFB/Quantum dots的片子以2000r/min的转速旋涂MgZnO纳米晶溶液，旋涂45秒。
6.Al电极
将制备好的样品片子放入真空腔体，蒸镀顶部电极。前10nm时蒸镀速率控制在
Figure PCTCN2020130633-appb-000001
范围内，10nm后蒸镀速率提升为
Figure PCTCN2020130633-appb-000002
左右。铝电极的厚度为100nm。
将实施例1～10和对比例1～4的量子点制成的光电器件进行性能测试，结果如表1所示。
外量子效率的测试方法：
采用Keithley2400测定量子点发光器件的电流密度密度-电压曲线，采用积分球(FOIS-1)结合海洋光学的光谱仪(QE-pro)测定光电器件的亮度。根据测定得到的电流密度密度与亮度计算光电器件的外量子效率。外量子效率表征在观测方向上光电器件发出的光子数与注入器件的电子数之间的比值，是表征器光电器件发光效率的重要参数，外量子效率越高，说明器件的发光效率越高。
表1
Figure PCTCN2020130633-appb-000003
表1中，EL指光电器件的发射峰值波长，EQE(ave)指的是光电器件的平均外量子效率，T50指的是100cd/m 2点亮条件下光电器件的亮度降低至初始亮度的50％所需要的老化时间，EQE max电流密度是指光电器件EQE达到最高时的工作电流密度，附图1～12示出了各个实施例和对比例的电流密度曲线图，从中可以看到器件的最高EQE以及对应的EQE max电流密度。
从表1可知，应该本申请量子点的光电器件在5mA/cm 2～20mA/cm 2的工作电流密度范围内，EQE即达到最大值，100cd/m 2点亮条件下T50寿命大于等于10000h，是一种低工作电流密度条件下，高光效、高寿命的光电器件。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改 进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (20)

  1. 一种量子点，包括内核和包覆所述内核的壳层，其特征在于，所述内核的材料为CdZnSe，所述壳层的材料为CdZnS，其中，所述壳层中Cd元素与S元素的摩尔比为0.15:1～0.4:1。
  2. 根据权利要求1所述的量子点，其特征在于，所述内核的平均粒径为3nm～10nm，所述壳层的厚度为3nm～10nm。
  3. 根据权利要求2所述的量子点，其特征在于，所述内核的平均粒径为5nm～9nm，所述壳层的厚度为3nm～5nm。
  4. 根据权利要求1～3中任一项所述的量子点，其特征在于，所述量子点的荧光发射波长为460nm～480nm。
  5. 根据权利要求4所述的量子点，其特征在于，所述量子点的荧光发射波长为470nm～480nm。
  6. 一种如权利要求1～5任一项所述的量子点的制备方法，其特征在于，包括步骤：
    制备内核；
    将所述内核与第一锌前驱体、脂肪胺、溶剂混合形成第一前驱体溶液，再将第一镉前驱体和第一硫前驱体分别或共同匀速加入至所述第一前驱体溶液以形成第二前驱体溶液，所述第二前驱体溶液中Cd元素与S元素的摩尔比为0.15:1～0.4:1；
    将所述第二前驱体溶液在第一温度下进行反应，以在所述内核的表面包覆形成壳层，得到量子点。
  7. 根据权利要求6所述的量子点的制备方法，其特征在于，所述内核的制备过程包括：将第二锌前驱体、第一硒前驱体、第二镉前驱体、溶剂混合，并在第二温度下反应，得到含第一合金量子点的溶液，将所述第一合金量子点提 纯作为所述内核。
  8. 根据权利要求7所述的量子点的制备方法，其特征在于，在所述第二温度下反应之后，所述内核的制备过程还包括加入第二硒前驱体，并在第三温度下反应，得到所述含第一合金量子点的溶液。
  9. 根据权利要求7或8所述的量子点的制备方法，其特征在于，所述内核的制备过程还包括：
    (1)将所述含第一合金量子点的溶液作为第一中间溶液；
    (2)将所述第一中间溶液与碳链长度小于等于8的短链脂肪酸锌、碳链长度大于等于12的长链脂肪酸混合，并在第四温度下反应，得到第二中间溶液；
    (3)将所述第二中间溶液与第三硒前驱体混合，并在第五温度下反应，以使所述第一合金量子点继续生长，得到含第二合金量子点的溶液；
    (4)将所述第二合金量子点提纯作为所述内核。
  10. 根据权利要求9所述的量子点的制备方法，其特征在于，至少重复n次步骤(2)和(3)进行继续生长，第n次重复时，第n+1合金量子点的溶液替代步骤(1)中的所述第一中间溶液，以得到含第n+2合金量子点的溶液，将所述第n+2合金量子点提纯作为所述内核，n为大于等于1正整数。
  11. 根据权利要求10所述的量子点的制备方法，其特征在于，所述长链脂肪酸与所述短链脂肪酸锌的摩尔比大于等于2:1。
  12. 根据权利要求11所述的量子点的制备方法，其特征在于，所述长链脂肪酸与所述短链脂肪酸锌的摩尔比为2:1～4:1。
  13. 根据权利要求10所述的量子点的制备方法，其特征在于，所述第三硒前驱体中的硒元素与所述第二中间溶液中的锌元素的摩尔比为1:2～2:1，所述第三硒前驱体中硒元素的摩尔浓度为0.5mmol/mL～4mmol/mL。
  14. 根据权利要求10所述的量子点的制备方法，其特征在于，所述第一合金量子点继续生长成第二合金量子点时，生长的厚度小于等于1.5nm；
    以及，所述第n+1合金量子点继续生长成第n+2合金量子点时，每重复一次所生长的厚度均小于等于1.5nm。
  15. 根据权利要求10所述的量子点的制备方法，其特征在于，第i次重复时，第i+1合金量子点的溶液替代步骤(1)中的所述第一中间溶液，以得到含第i+2合金量子点的溶液，将所述第i+2合金量子点提纯作为所述内核，所述i为小于所述n的正整数。
  16. 一种如权利要求1～5任一项所述的量子点的制备方法，其特征在于，包括步骤：
    制备内核；
    将所述内核与第一锌前驱体、脂肪醇、溶剂混合形成第一前驱体溶液，再将第一镉前驱体和第一硫前驱体分别或共同匀速加入至所述第一前驱体溶液以形成第二前驱体溶液，所述第二前驱体溶液中Cd元素与S元素的摩尔比为0.15:1～0.4:1；
    将所述第二前驱体溶液在第一温度下进行反应，以在所述内核的表面包覆形成壳层，得到量子点。
  17. 根据权利要求16所述的量子点的制备方法，其特征在于，所述脂肪醇选自碳链长度为12～30的脂肪醇。
  18. 一种量子点组合物，其特征在于，包括权利要求1～5任一项所述的量子点或包括由权利要求6～17任一项所述的制备方法制备而成的量子点。
  19. 一种光电器件，其特征在于，包括权利要求1～5任一项所述的量子点或包括由权利要求6～17任一项所述的制备方法制备而成的量子点。
  20. 根据权利要求19所述的光电器件，其特征在于，所述光电器件为量子点发光二极管，所述量子点发光二极管达到最高外量子效率时所需工作电流密度为5mA/cm 2～20mA/cm 2，且所述最高外量子效率为9.6％～12.6％。
PCT/CN2020/130633 2019-11-21 2020-11-20 量子点及其制备方法、量子点组合物、光电器件 WO2021098857A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US17/777,657 US20220403240A1 (en) 2019-11-21 2020-11-20 Quantum dot and preparation methods for the same, and photoelectric device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201911147636.8 2019-11-21
CN201911147636.8A CN112824481B (zh) 2019-11-21 2019-11-21 量子点及其制备方法、应用

Publications (1)

Publication Number Publication Date
WO2021098857A1 true WO2021098857A1 (zh) 2021-05-27

Family

ID=75907485

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/130633 WO2021098857A1 (zh) 2019-11-21 2020-11-20 量子点及其制备方法、量子点组合物、光电器件

Country Status (3)

Country Link
US (1) US20220403240A1 (zh)
CN (1) CN112824481B (zh)
WO (1) WO2021098857A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116169562B (zh) * 2023-02-28 2024-01-23 上海铭锟半导体有限公司 一种胶体量子点光源集成结构及其制备方法
CN116574500B (zh) * 2023-05-26 2023-11-14 北京北达聚邦科技有限公司 一种高光密度绿光量子点及其制备方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103384794A (zh) * 2010-12-23 2013-11-06 Qd视光有限公司 包含量子点的光学元件
CN104205368A (zh) * 2012-02-05 2014-12-10 Qd视光有限公司 半导体纳米晶体、其制备方法、组合物、以及产品
CN108531185A (zh) * 2018-06-07 2018-09-14 嘉兴纳鼎光电科技有限公司 一种量子点及其合成方法
CN108587628A (zh) * 2018-06-07 2018-09-28 玻尔兹曼智能科技（苏州）有限公司 一种量子点的合成方法
CN109988555A (zh) * 2017-12-29 2019-07-09 Tcl集团股份有限公司 一种量子点及其制备方法与应用
CN110055073A (zh) * 2019-05-07 2019-07-26 纳晶科技股份有限公司 一种核壳量子点及其制备方法、量子点光电器件
CN110129054A (zh) * 2019-04-10 2019-08-16 纳晶科技股份有限公司 核壳量子点及其制备方法、量子点光电器件

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007143197A2 (en) * 2006-06-02 2007-12-13 Qd Vision, Inc. Light-emitting devices and displays with improved performance
CN108264901B (zh) * 2016-12-30 2022-08-05 Tcl科技集团股份有限公司 具有漏斗型能级结构的发光材料、制备方法及半导体器件
CN109097022A (zh) * 2017-06-20 2018-12-28 苏州星烁纳米科技有限公司 一种核壳结构量子点的制备方法
CN109294585B (zh) * 2018-09-28 2022-04-19 纳晶科技股份有限公司 一种CdZnSeS合金量子点及其制备方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103384794A (zh) * 2010-12-23 2013-11-06 Qd视光有限公司 包含量子点的光学元件
CN104205368A (zh) * 2012-02-05 2014-12-10 Qd视光有限公司 半导体纳米晶体、其制备方法、组合物、以及产品
CN109988555A (zh) * 2017-12-29 2019-07-09 Tcl集团股份有限公司 一种量子点及其制备方法与应用
CN108531185A (zh) * 2018-06-07 2018-09-14 嘉兴纳鼎光电科技有限公司 一种量子点及其合成方法
CN108587628A (zh) * 2018-06-07 2018-09-28 玻尔兹曼智能科技（苏州）有限公司 一种量子点的合成方法
CN110129054A (zh) * 2019-04-10 2019-08-16 纳晶科技股份有限公司 核壳量子点及其制备方法、量子点光电器件
CN110055073A (zh) * 2019-05-07 2019-07-26 纳晶科技股份有限公司 一种核壳量子点及其制备方法、量子点光电器件

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
KIMIHIRO SUSUMU, LAUREN D. FIELD, EUNKEU OH, MICHAEL HUNT, JAMES B. DELEHANTY, VALLE PALOMO, PHILIP E. DAWSON, ALAN L. HUSTON, IGO: "Purple‑, Blue‑, and Green-Emitting Multishell Alloyed Quantum Dots:Synthesis, Characterization, and Application for Ratiometric Extracellular pH Sensing", CHEMISTRY OF MATERIALS, vol. 29, no. 17, 30 August 2017 (2017-08-30), pages 7330 - 7344, XP055675664, ISSN: 0897-4756, DOI: 10.1021/acs.chemmater.7b02174 *

Also Published As

Publication number Publication date
CN112824481B (zh) 2022-07-29
US20220403240A1 (en) 2022-12-22
CN112824481A (zh) 2021-05-21

Similar Documents

Publication Publication Date Title
CN108251117B (zh) 核壳量子点及其制备方法、及含其的电致发光器件
WO2021098857A1 (zh) 量子点及其制备方法、量子点组合物、光电器件
CN108075020B (zh) 一种基于铯铅卤钙钛矿薄膜材料的发光二极管及其制备方法
CN110526277B (zh) 掺杂氧化锌纳米晶的制备方法、电子传输层、发光器件
EP2452372A2 (en) Stable and all solution processable quantum dot light-emitting diodes
KR101734465B1 (ko) 단일 양자점 에미터를 포함하는 백색 전기 발광 소자 및 그 제조방법
CN110943178A (zh) 一种自组装多维量子阱CsPbX3钙钛矿纳米晶电致发光二极管
CN111509142B (zh) 核壳量子点、量子点发光二极管、量子点组合物、显示器件
KR101665450B1 (ko) 인듐갈륨계 금속 질화물의 양자점을 포함하는 발광소자 및 이의 제조 방법, 및 이를 이용한 발광장치
US11840655B2 (en) Yellow-red spectral quantum dot, synthesis method therefor and application thereof
CN109666477B (zh) 一种核壳量子点及其制备方法、电子器件
WO2020142482A1 (en) Quantum dot light-emitting diodes comprising hole transport layers
CN113921731A (zh) 基于Co掺杂ZnO作为电子传输层的电致发光LED及其制备方法
CN112824477B (zh) 核壳量子点的制备方法及其应用
CN111218284B (zh) 一种核壳量子点及其制备方法、电子器件
Kuang et al. Optical properties of ultraviolet quantum dot light-emitting devices using ZnO-cores with a MgO-shell
WO2022143551A1 (zh) 量子点发光二极管的制备方法
CN114672314A (zh) 核壳结构量子点及其制备方法，量子点发光薄膜和二极管
WO2024109344A1 (zh) 量子点组合物的制备方法、发光材料及发光器件
CN112824476B (zh) 量子点、制备方法及包含其的量子点组合物、光电器件
CN115627166B (zh) 一种量子点及其制备方法和电致发光器件
CN113497191B (zh) 一种光电器件及其制备方法
WO2019099647A1 (en) Light-emitting device structures for blue light and other applications
CN111117595B (zh) 蓝光核壳量子点、其制备方法以及应用
WO2023284728A1 (zh) 发光装置及量子点led的使用方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20890949

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20890949

Country of ref document: EP

Kind code of ref document: A1